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Benefit determinations are based on the applicable contract language in effect at the time the
services were rendered. Exclusions, limitations or exceptions may apply. Benefits may vary
based on contract, and individual member benefits must be verified. Wellmark determines medical
necessity only if the benefit exists and no contract exclusions are applicable. This medical
policy may not apply to FEP. Benefits are determined by the Federal Employee Program.

This Medical Policy document describes the status of medical technology at the time the document
was developed. Since that time, new technology may have emerged or new medical literature may
have been published. This Medical Policy will be reviewed regularly and be updated as scientific
and medical literature becomes available.

Description:

One of the major functions of the pancreas is the production of two hormones, insulin and glucagon. The production of these hormones take place in endocrine cell clusters located throughout the pancreas called the islet of Langerhans. The islet of Langerhans make up approximately 1 percent to 2 percent of the total pancreas.

There are approximately one million islets in a healthy adult. Most islet cells are concentrated towards the tail end of the pancreas. Islets are composed of two types of cells:

Alpha Cells: which produce glucagon, a hormone that raises the level of glucose (sugar) in the blood.

Beta Cells: which produce insulin, a hormone that reduces the level of glucose (sugar) in the blood by helping the body use glucose for energy.

Islet cell transplantation has been investigated to treat patients with chronic pancreatitis, and more recently type 1 diabetes.

Chronic Pancreatitis Chronic pancreatitis is inflammation of the pancreas that does not heal or improve, it gets worse over time and leads to permanent damage. Chronic pancreatitis eventually impairs an individual’s ability to digest food and make pancreatic hormones. Individuals with chronic pancreatitis can experience intractable pain that can only be relieved with a total or near total pancreatectomy. However, the pain relief must be balanced against the certainty that the individual will be rendered an insulin-dependent diabetic.

Autologous islet cell transplantation has been investigated as a technique to prevent this serious morbidity of surgically induced diabetes due to the removal of the individual’s pancreas. The transplant is generally performed during the pancreatectomy procedure, islet cells are isolated from the resected pancreas using enzymes, and a suspension of the cells is injected into the portal vein of the patient’s liver. Once implanted, the beta cells in these islets begin to make and release insulin. Because the body recognizes these islet cells as its own, there is no rejection of these cells by the patient’s body.

Although the published literature regarding autologous islet cell transplant is limited, the procedure appears to significantly decrease the occurrence of surgically induced diabetes after total or near total pancreatectomy in patients with chronic pancreatitis. Also, this procedure is not associated with serious complications or morbidity. The evidence is insufficient to demonstrate the efficacy of autologous islet cell transplantation performed for any other indication.

Type 1 Diabetes MellitusType 1 diabetes is a chronic illness characterized by the body’s inability to produce insulin due to the autoimmune destruction of the beta cells in the pancreas. Islet cell autoantibodies (ICAs) are theorized to cause the individual to reject their own islet cells, leading to insulin deficiency. Individuals with type 1 diabetes do not have viable beta cells and therefore, cannot receive an autologous islet cell transplant.

Allogeneic islet cell transplant has been proposed as a treatment for patients with type 1 diabetes to restore normoglycemia (normal glucose levels) and to reduce or eliminate the long-term complications of diabetes such as retinopathy, neuropathy, nephropathy, and cardiovascular disease. Islet cell transplantation potentially offers an alternative to whole-organ pancreas transplantation.

Allogeneic islet cell transplant is a procedure in which islets are obtained from deceased organ donor and are purified, processed and transferred into the transplant patient. A limitation of allogeneic islet cell transplantation is that 2 or more donor organs are usually required for successful transplantation. A pancreas that is rejected for whole-organ transplant is typically used for islet transplantation. Transplant patients typically receive two infusions with an average of 400,000 to 500,000 islets per infusion. Once implanted in the liver, the beta cells in these islets begin to make and release insulin. The patient will be started on immuosuppressive therapy to prevent allograft rejection.

The techniques for allogeneic islet cell transplants are evolving, and the impact on the net health outcome is still uncertain. Longer follow up is needed to evaluate the long-term safety and its impact on complications of diabetes mellitus.

Regulatory StatusIslet cells are subject to regulation by the U.S. Food and Drug Administration (FDA), which classifies allogeneic islet cells transplantation as somatic cell therapy, requiring pre-market approval. Islets also meet the definition of a drug under the federal Food, Drug, and Cosmetic Act. Clinical studies to determine safety and effectiveness outcomes of allogeneic islet cell transplantation must be conducted under FDA investigational new drug (IND) regulation.

Autologous pancreatic islet cell transplantation may be considered medically necessary as an adjunct to a total or near-total pancreatectomy in patients with chronic pancreatitis.

Autologous pancreas islet cell transplantation is considered investigational when the above criteria is not met and for all other indications because the safety and/or effectiveness of this procedure for all other indications can not be established based on available peer reviewed literature.

Allogeneic pancreatic islet cell transplantation is considered investigational for all indications including the treatment of type 1 diabetes.

The techniques for allogeneic islet cell transplants are evolving; the impact on net health outcomes is still uncertain. Longer follow up with larger numbers of patients is needed before conclusions can be drawn about the safety of allogeneic islet transplantation and its impact on complications of diabetes mellitus, thus the procedure is considered investigational.

Wellmark medical policies address the complex issue
of technology assessment of new and emerging treatments, devices,
drugs, etc.They are developed to
assist in administering plan benefits and constitute neither offers of
coverage nor medical advice. Wellmark medical policies contain only a
partial, general description of plan or program benefits and do not
constitute a contract. Wellmark does not provide health care services
and, therefore, cannot guarantee any results or outcomes.
Participating providers are independent contractors in private
practice and are neither employees nor agents of Wellmark or its
affiliates. Treating providers are solely responsible for medical
advice and treatment of members. Our medical policies may be updated
and therefore are subject to change without notice.